Systems and methods for displaying virtual railroad signs

ABSTRACT

A method for operating a railroad vehicle without reference to physical railroad signs placed along a railroad track includes determining a current location of the railroad vehicle along the railroad track based on the determined current location of the railroad vehicle, automatically selecting a virtual railroad sign from one or more databases containing a plurality of virtual railroad signs, each of the plurality of virtual railroad signs stored in the one or more databases being associated with (i) a location along the railroad track and (ii) a message, and displaying, on an electronic display device a railroad track indicia representative of a segment of the railroad track, a railroad vehicle indicia representative of at least a portion of the railroad vehicle, and an indicia representative of the associated message of the selected virtual railroad sign.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Application No. 62/786,076, filed Dec. 28, 2018, which is hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to railroad signs, and more particularly, to systems and methods for automatically displaying a plurality of virtual railroad signs such that a railroad vehicle can be operated without reference to physical signs placed along the railroad track.

BACKGROUND

Railroad vehicle operators (engineers) rely on physical signs placed along the railroad track to operate the railroad vehicle. For example, mileposts indicate a location of the railroad vehicle, whistle boards indicate when the engineer should blow the whistle/horn, limit signs tell the engineer where to stop at a switch to avoid collisions with other trains, and speed limit signs tell the engineer how fast to go. If the location of these physical signs in changed, or if the physical sign is removed entirely, this may inhibit the engineer's ability to safely operate the railroad vehicle and/or result in the railroad's non-compliance with certain government regulations regarding the maintenance of railroad signs. The present disclosure is directed to solving these and other problems.

SUMMARY

According to some implementations of the present disclosure, a method for operating a railroad vehicle on a railroad track without reference to physical railroad signs located generally along the railroad track includes determining a current location of the railroad vehicle along the railroad track, based on the determined current location of the railroad vehicle, automatically selecting a virtual railroad sign from one or more databases containing a plurality of virtual railroad signs, each of the plurality of virtual railroad signs stored in the one or more databases being associated with (i) a respective location along the railroad track and (ii) a respective message, and displaying, on an electronic display device a railroad track indicia representative of a segment of the railroad track, a railroad vehicle indicia representative of at least a portion of the railroad vehicle, and an indicia representative of the associated message of the selected virtual railroad sign.

According to some implementations of the present disclosure, a method for operating a railroad vehicle without reference to physical railroad signs placed along a railroad track includes determining a current location of the railroad vehicle along the railroad track, based on the determined current location of the railroad vehicle, automatically selecting a plurality of virtual railroad signs from one or more databases, each of the plurality of virtual railroad signs being associated with (i) a location along the railroad track and (ii) a message, and displaying, on an electronic display device a railroad track indicia representative of a segment of the railroad track, a railroad vehicle indicia representative of at least a portion of the railroad vehicle, and for each of the selected plurality of virtual railroad signs, an indicia representative of the associated message.

According to some implementations of the present disclosure, a method for operating a railroad vehicle on a railroad track without reference to physical railroad signs located along the railroad track includes determining a current location of the railroad vehicle along the railroad track, based on the determined current location of the railroad vehicle, automatically selecting a plurality of virtual railroad signs from one or more databases, each of the plurality of virtual railroad signs being associated with (i) a respective location along the railroad track and (ii) a respective message, and displaying, on an electronic display device a railroad track indicia representative of a segment of the railroad track, a railroad vehicle indicia representative of at least a portion of the railroad vehicle, and for each of the selected plurality of virtual railroad signs, an indicia representative of the associated message.

According to some implementations of the present disclosure, a system for operating a railroad vehicle without reference to physical signs placed along a railroad track includes a GPS module configured to generate location data indicative of a location of the railroad vehicle on the railroad track, a memory device storing one or more databases of virtual railroad signs, each of the virtual railroad signs being associated with (i) a respective location along the railroad track and (ii) a respective message, an electronic display device, and one or more processors configured to determine a current location of the railroad vehicle based on the location data, based on the determined current location of the railroad vehicle, automatically select a plurality of virtual railroad signs from the database of virtual railroad signs, the associated location of each of the selected plurality of virtual railroad signs being within a predetermined distance of the current location of the railroad vehicle, and cause the electronic display device to display a railroad vehicle indicia representative of at least a portion of the railroad vehicle, a railroad track indicia representative of a segment of the railroad track, and for each of the selected plurality of virtual railroad signs, an indicia representative of the associated message.

According to some implementations of the present disclosure a system for automatically displaying virtual railroad signs includes a railroad vehicle configured to move along a railroad track, the railroad vehicle including a Positive Train Control (PTC) system, a GPS module coupled to the railroad vehicle and being configured to generate location data indicative of a location of the railroad vehicle along the railroad track, an electronic memory device for storing one or more databases containing virtual railroad signs, each of the virtual railroad signs being associated with (i) a respective location along the railroad track and (ii) respective a message, an electronic display device coupled to the railroad vehicle such that an engineer operating the railroad vehicle can view the electronic display device, and one or more processors configured to determine a current location of the railroad vehicle on the railroad track based on location data from the GPS module, automatically select a plurality of virtual railroad signs from the database of virtual railroad signs, the associated location of each of the selected plurality of virtual railroad signs being within a predetermined distance from the determined current location of the railroad vehicle, and cause the electronic display device to display (i) a railroad vehicle indicia representative of at least a portion of the railroad vehicle, (ii) a first railroad track indicia representative of the first segment of the railroad track, and (iii) the first plurality of virtual railroad signs at corresponding locations along the first railroad track indicia.

The above summary is not intended to represent each embodiment or every aspect of the present invention. Additional features and benefits of the present invention are apparent from the detailed description and figures set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of a system for automatically displaying virtual railroad signs and a railroad vehicle according to some implementations of the present disclosure;

FIG. 2A is a plan view of the railroad vehicle of FIG. 1 at a first location along a railroad track including a plurality of physical railroad signs according to some implementations of the present disclosure;

FIG. 2B is a plan view of the railroad vehicle of FIG. 1 at a second, subsequent location along the railroad track of FIG. 2A according to some implementations of the present disclosure;

FIG. 3A illustrates an indicia representative of the railroad vehicle, an indicia representative of the railroad track of FIG. 2A, and a plurality of virtual railroad signs displayed on the electronic display device of the system of FIG. 1 according to some implementations of the present disclosure;

FIG. 3B illustrates an indicia representative of the railroad vehicle, an indicia representative of the railroad track of FIG. 2B, and a plurality of virtual railroad signs displayed on the electronic display device of the system of FIG. 1 according to some implementations of the present disclosure;

FIG. 4 is a flowchart of an example method for operating a railroad vehicle without reference to physical railroad signs placed along a railroad track according to some implementations of the present disclosure

FIG. 5 is a two-dimensional map of a railroad according to some implementations of the present disclosure; and

FIG. 6 is a linearized version of the two-dimensional map of the railroad of FIG. 5 according to some implementations of the present disclosure.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Railroad vehicle operators (engineers) rely on physical signs and signals placed adjacent to the railroad track (e.g., subways, elevated trains, high speed rail, monorails, trams, etc.) to operate the railroad vehicle. Examples of physical railroad signs include, mileposts (indicating a reference location), whistle boards (indicating when the engineer should blow the horn/whistle), limit signs (indicating when the engineer should stop the railroad vehicle at a switch to avoid collisions with other trains), speed limit signs (indicating how fast the engineer can operable the railroad vehicle), curve signs (indicating an upcoming curved or non-linear section of the railroad track), tunnel signs (indicating an upcoming railroad tunnel), road crossing signs (indicating an intersecting vehicle/pedestrian roadway), rail crossing (indicating an intersecting railroad track), overhead bridge sign (indicating an upcoming overhead bridge), grade signs (indicating a grade or incline of the railroad track), and the like. These physical railroad signs can be placed at various locations along the railroad track, including, for example, above the railroad track (e.g., an overhead sign) or on either side of the railroad track.

Many railroad vehicles (e.g., passenger trains, freight trains, etc.) include a so-called Positive Train Control (PTC) system. In many jurisdictions (e.g., the United States), PTC systems are required by government regulations. For example, all North American freight trains utilize PTC systems. Generally, the PTC system receives information about the location of the railroad vehicle (e.g., from a GPS navigation system) and information regarding where the railroad vehicle is allowed to safely travel. Using this information, the PTC system prevents or overrides unsafe movement of the railroad vehicle (e.g., reduces the speed of the railroad vehicle, stops the railroad vehicle, etc.) PTC systems rely on a database of physical railroad signs (e.g., speed limit signs) which are input into PTC algorithms to control movement of the railroad vehicle (e.g., enforce collision avoidance, reduce speed, etc.) In the United States, the Federal Railroad Administration (“FRA”) requires that all PTC systems have an accurate database containing precise GPS coordinates of each physical railroad sign. The total number of physical signs in such a database may be between 400,000 and 600,000 signs. In particular, the FRA requires that the GPS coordinates of each sign stored in the database are within 7.2 feet of the actual GPS coordinates of the physical sign.

Railroads face several challenges continuously maintaining a database of GPS coordinates of physical signs within the applicable tolerances because the physical signs are often moved for a variety of reasons, whether intentionally or unintentionally. For example, railroad maintenance workers often must temporarily remove physical signs when replacing fouled ballast (stone material that supports the railroad track). After the ballast is replaced, workers place the railroad signs back in the general area of their original position. This process is often imprecise, meaning that the GPS coordinates stored in the PTC system database may no longer correspond to the new, actual GPS coordinates of the railroad sign. As an another example, a railroad snowplow may knock over physical signs when removing snow from the railroad track. Often, these signs are not repositioned until the snow is clear (e.g., in the spring) and is often done so in a relatively imprecise manner. As a result of this movement of the signs, railroads must continuously resurvey or audit the GPS coordinates of each of the physical signs to ensure that the PTC database is in compliance with applicable government regulations. Resurveying the physical signs may require personnel to travel to each of the physical signs and record the sign's GPS coordinates using a mobile device. Other surveying methods may require complicated detection systems (e.g., light detection and ranging (“LIDAR”) sensors and/or simultaneous localization and mapping (“SLAM”) sensors) coupled to a railroad vehicle to update the GPS coordinates of the physical railroad signs.

Referring to FIG. 1, a system 10 includes one or more processors 12 (hereinafter “processor”), one or more memory devices 14 (hereinafter “memory”), one or more electronic display devices 18 (hereinafter “electronic display device”), a communication module 20, a GPS module 22, and one or more location sensors 24. The system 10 is coupled to or located on a railroad vehicle 100 (e.g., a locomotive, a railcar, a passenger car, a freight car, a subway train, a vehicle configured to move along both a conventional road surface and railroad tracks, etc.) As described herein, the system 10 can be used to automatically display one or more virtual railroad signs on the electronic display device 18 such that an engineer can operate the railroad vehicle without reference to physical signs placed along the railroad track. In other words, the physical signs places along the railroad track can be removed if desired.

The processor 12 of the system 10 is communicatively coupled to the memory device 14, the electronic display device 18, the communication module 20, the GPS module 22, and the one or more location sensors 24, and is generally used to control the operation of these various components of the system 10 and implement the methods described herein. The processor 12 can be a general or special purpose processor or microprocessor, and the system 10 can include any suitable number of processors (e.g., one processor, two processors, four processors, ten processors, etc.)

The memory device 14 is generally used to store machine readable instructions that are executable by the processor 12. In particular, the memory device 14 stores a virtual sign database 16. The virtual sign database 16 contains an associated location (e.g., as defined by GPS coordinates) and associated message (e.g., a numerical speed limit) for a plurality of virtual railroad signs. The associated location of each of the plurality of virtual railroad signs is the location along the railroad track where a physical railroad sign would be placed instead of (or in addition to), the virtual railroad sign. Methods for generating the virtual sign database 16 such that the virtual railroad signs contained therein correspond to where physical railroad signs would be positioned along the railroad track are discussed in further detail herein. The memory device 14 can be any suitable computer readable storage device or media, such as, for example, a random or serial access memory device, a hard drive, a solid state drive, a flash memory device, etc.

While the memory device 14 is shown as including a single virtual sign database 16, in some implementations, the memory device 14 can include a plurality of virtual sign databases (e.g., two databases, five databases, ten databases, etc.) For example, a first database can contain the associated location (e.g., GPS coordinates) of the virtual railroad signs and a second database can contain the associated message (e.g., numerical speed limit) of the virtual railroad signs. Further, while the memory device 14 of the system 10 is shown as being coupled to (e.g., located on) the railroad vehicle 100, alternatively, in some implementations, the memory device 14 can be decoupled from the railroad vehicle 100 (e.g., located on or in a remote device such as a remote server). In such implementations, the communication module 20 communicatively couples the memory device 14 to the processor 12.

The electronic display device 18 is a human-machine interface (HMI) including a graphical user interface (GUI) that can display images (e.g., still images, video images, or both). As described in detail herein, the electronic display device 18 can display, for example, an indicia representative of a message of a virtual railroad sign, an indicia representative of at least a portion of the railroad vehicle 100, and/or an indicia representative of a portion of the railroad track. The electronic display device 18 can be, for example, a general or special purpose desktop computer, laptop computer, tablet computer, smartphone, display monitor, television, LED display, LCD display, or the like, or any combination thereof. The electronic display device 18 can also include an input interface such as, for example, a touchscreen or touch-sensitive substrate, a mouse, a keyboard, or any sensor system configured to sense inputs made by a human user interacting with the electronic display device 18.

As shown, the electronic display device 18 is coupled to (e.g., located on or in) the railroad vehicle 100. More specifically, in some implementations, the electronic display device 18 is located in a cab of the railroad vehicle 100 such that the electronic display device 18 can be viewed by an engineer operating the railroad vehicle. For example, in some implementations, the electronic display device 18 can be a head-up display (HUD) that displays image(s) without requiring the engineer to look away from the usual viewpoint when operating the railroad vehicle. The HUD can include a windshield projection to display one or more images on the windshield of the railroad vehicle 100. While the electronic display device 18 is shown as being coupled to (e.g., located on or in) the railroad vehicle 100, in some implementations, the electronic display device 18 is decoupled from the railroad vehicle 100. In such implementations, the electronic display device 18 can be integrated in a mobile device such as a smartphone, tablet, laptop computer, or the like.

The communication module 20 is communicatively coupled to the processor 12 and is generally used to communicate data or other information in digital or analog form to and from systems external to the system 10 (e.g., a remote server). Examples of communication interfaces for the communication module 20 include a wired network interface or a wireless network interface. As shown, the communication module 20 of the system 10 is coupled to the railroad vehicle 100. Further, the communication module 20 is communicatively coupled to the memory device 14 via the processor 12. Thus, in some implementations, the communication module 20 can transmit an updated or substantially real-time virtual railroad sign data base from a remote device to the system 10, replacing the virtual sign database 16 previously stored in the memory device 14.

The GPS module 22 is coupled to the railroad vehicle 100 and is configured to receive GPS signals for determining a location (e.g., expressed in latitude and longitude, or other coordinates) of the railroad vehicle 100. As described herein, the location of the railroad vehicle 100 along a railroad track can be expressed in terms of a distance relative to the railroad track. Among the various railroad signs described herein are mile markers. In other words, the location of the railroad vehicle 100 is expressed in reference to mile markers (e.g., the current location of the railroad vehicle 100 is mile 5.9 of the railroad track). To express the location of the railroad vehicle 100 in this manner (e.g., as opposed to purely in the form of GPS coordinates), the processor 12 can compare the GPS coordinates determined by the GPS module 20 to a look-up table (e.g., stored in the memory device 14) and/or determine a distance between the GPS coordinates of the railroad vehicle 100 and known GPS coordinates of the nearest milepost.

During operation, the railroad vehicle 100 may travel in areas (e.g., a tunnel) where the GPS module 22 cannot acquire a GPS signal from which the location of the railroad vehicle 100 can be determined. For this scenario, the system 10 optionally includes one or more location sensors 24 that are configured to determine the location of the railroad vehicle 100 without the use of GPS signals. For example, in some implementations, the one or more location sensors 24 includes an optical encoder that is coupled to an end of an axle of the railroad vehicle 100 to detect rotational position changes. In such implementations, the optical encoder can be used to determine the location of the railroad vehicle 100 in terms of a distance traveled from an initial position (e.g., the last known location of the railroad vehicle 100). In other implementations, the one or more location sensors 24 includes a radio-frequency identification (RFID) reader coupled to the railroad vehicle 100 and being configured to receive location information from RFID tags positioned on or adjacent to the railroad. The RFID tags store information such as GPS coordinates or a distance relative to mileposts or other landmarks from which the system 10 can determine the location of the railroad vehicle 100 without the use of GPS.

As described herein, the railroad vehicle 100 is configured to move along a railroad track (e.g., railroad track 200 shown in FIGS. 2A and 2B), which can include, for example, one or more running rails, a power rail, crossties, fasteners, joint bars, ballast, overhead power lines, switches, or the like, or any combination thereof. In some implementations, the railroad vehicle 100 includes one or more cameras 112 (hereinafter “camera”) configured to generate image data reproducible as one or more images the railroad. The camera 112 can be a digital camera that generates video images, still images, or both; and can optionally include zooming ability (e.g., optical and/or digital zoom). As shown, the camera 112 is communicatively coupled to the processor 12 of the system 10. The railroad vehicle 100 also includes a Positive Train Control system (“PTC”) 114. As described herein, the PTC system 114 is generally used to control the movement of the railroad vehicle 100 along the railroad track. As shown, the PTC system 114 is communicatively coupled to the processor 12 of the system 10. In some implementations, the railroad vehicle 100 can also include a light detection and ranging (“LIDAR”) sensor, a simultaneous localization and mapping (“SLAM”) sensor, or both. The LIDAR sensor and/or SLAM sensor can be used to generate a three-dimensional representation of the railroad track and its surroundings, which can be stored in the memory device 14 and/or transmitted to a remote device via the communication module 20.

While the system 10 is shown in FIG. 1 as including all of the components described herein, more or fewer components can be included in a system. For example, an alternative system (not shown) includes the processor 12, the memory device 14, the display device 18, and the GPS module 22. Thus, various systems for automatically displaying virtual railroad signs and/or operating the railroad vehicle 100 without reference to physical railroad signs placed along the railroad track can be formed using any portion of the components described herein.

Referring to FIG. 2A, a plan view of the railroad vehicle 100 (FIG. 1) and a railroad track 200 is illustrated. As shown, the railroad track 200 includes a substantially linear (e.g., straight) section 210 and substantially non-linear (e.g., curved) section 220. In this example, the railroad vehicle 100 generally travels along the railroad track 200 in the direction of arrow A. As shown, the railroad vehicle 100 is positioned at a first location (relative to a second, subsequent location shown in FIG. 2B).

A plurality of physical railroad signs 230 are placed along or adjacent to the railroad track 200, including a plurality of milepost signs 232 a-232 d, a plurality of speed limit signs 234 a-234 b, and a whistle board sign 236. The plurality of milepost signs 232 a-232 d are positioned along the railroad track 200 at regular intervals of one mile and include a first milepost sign 232 a (indicating a first mile of the railroad track 200), a second milepost sign 232 b (indicating a second mile of the railroad track 200), a third milepost sign 232 c (indicating a third mile of the railroad track 200), a fourth milepost sign 232 d (indicating a fourth mile of the railroad track 200), and a fifth milepost sign 232 e (indicating a fifth mile of the railroad track 200). The plurality of speed limit signs 234 a-234 b includes a first speed limit sign 234 a and a second speed limit sign 234 b. As shown, the first speed limit sign 234 a is positioned at the first mile of the railroad track 200 (e.g., at the same or similar position as the first milepost sign 232 a). The first speed limit sign 234 a communicates to the engineer operating the railroad vehicle 100 that the speed limit after the first milepost sign 232 a is 60 miles per hour. The second speed limit sign 234 b is positioned at the fourth mile of the railroad track 200 (e.g., at the same or similar position as the fourth milepost sign 234 b). The second speed limit sign 234 b communicates to the engineer operating the railroad vehicle 100 that the speed limit after the fourth milepost sign 232 d is 45 miles per hour. In other words, the second speed limit sign 234 b communicates to the engineer to slow down the railroad vehicle 100 as it is traveling on the substantially non-linear section 220 of the railroad track 200. The whistle board sign 236 is positioned between the first milepost sign 232 a and the second milepost sign 232 b and communicates to the engineer operating the railroad vehicle 100 to blow the railroad vehicle 100 whistle/horn. More specifically, the whistle board sign 236 is positioned prior to (relative to arrow A) a crossing 250 (e.g., a rail crossing, a roadway crossing, a pedestrian crossing, etc.) such that the engineer blows the railroad vehicle 100 whistle/horn as a warning that the railroad vehicle 100 is approaching the crossing 250.

FIG. 3A illustrates an indicia 310 representative of the railroad vehicle 100 (FIGS. 1 and 2A), an indicia 320 representative of a segment of the railroad track 200 (FIG. 2A) a plurality of virtual railroad signs 330 corresponding to the plurality of physical railroad signs 232 (FIG. 2A) displayed on the electronic display device 18 (FIG. 1). As shown, the indicia 310 representative of the railroad vehicle 100 is an image or depiction of a railroad locomotive, although other images are possible (e.g., based on the kind of railroad vehicle, based on the personnel using the electronic display device 18, etc.) As shown, the indicia 320 representative of a segment of the railroad track 200 is linear, whereas the corresponding segment of the railroad track 200 includes a substantially linear section 210 and a substantially non-linear section 220, as shown in FIG. 2A.

The electronic display device 18 also displays a current location 300 of the railroad vehicle 100. In this example, current location 300 is expressed in terms of a distance along the railroad track 200 (mile 0.9), although the current location 300 can also be expressed in other ways (e.g., in GPS coordinates). While not shown in FIG. 3A, the electronic display device 18 can also display other information regarding the status of the railroad vehicle 100, such as, for example, brake pipe pressure, brake cylinder pressure, break pipe reduction, speed, acceleration, end-of-train status, a length of the train, or the like, or any combination thereof.

The plurality of virtual railroad signs 330 includes a plurality of virtual milepost signs 332 a-332 e, a plurality of virtual speed limit signs 334 a-334 b, and a virtual whistle board sign 336. The plurality of virtual milepost signs 332 a-332 e correspond to the plurality of physical milepost signs 232 a-232 e (FIG. 2A). More specifically, a first virtual milepost sign 332 a includes an indicia 333 a (in this example, the number 1) to communicate the message of the first virtual milepost sign 332 a (e.g., the beginning of the first mile of the railroad track 200), second virtual milepost sign 332 b includes an indicia 333 b (in this example, the number 2) to communicate the message of the second virtual milepost sign 332 b (e.g., the beginning of the second mile of the railroad track 200), third virtual milepost sign 332 c includes an indicia 333 c (in this example, the number 3) to communicate the message of the third virtual milepost sign 332 c (e.g., the beginning of the third mile of the railroad track 200), the fourth virtual milepost sign 332 d includes an indicia 333 d (e. in this example, the number 4) to communicate the message of the fourth virtual milepost sign 332 d (e.g., the beginning of the fourth mile of the railroad track 200), and the fifth virtual milepost sign 332 e includes an indicia 333 e (in this example, the number 5) to communicate the message of the fifth virtual milepost sign 332 e (e.g., the beginning of the fifth mile of the railroad track 200). As shown, each of the plurality of virtual milepost signs 332 a-332 e are spaced evenly apart on the electronic display device 18 (FIG. 3A), just as the physical milepost signs 232 a-232 e are evenly spaced are along the railroad track 200 (FIG. 2A). As shown, each of the plurality of virtual railroad signs 330 has a generally square boundary in which the indicia representative of the associated message is contained when displayed on the electronic display device 18. While each of the plurality of virtual railroad signs 330 is shown as including a generally square boundary, other boundary shapes and sizes are possible (e.g., rectangular, circular, triangular, polygonal, etc.)

The plurality of virtual speed limit signs 334 a-334 b (FIG. 3) correspond to the plurality of physical speed limit signs 234 a-234 b (FIG. 2A). A first virtual speed limit sign 334 a corresponds to the first physical speed limit sign 234 a (FIG. 2A) and includes an indicia 335 a (e.g., a number) representative of the speed limit (in this example, 60 miles per hour). Likewise, a second virtual speed limit sign 334 b corresponds to the second physical speed limit sign 234 b (FIG. 2A) and includes an indicia 335 b (e.g., a number) representative of the speed limit (in this example, 45 miles per hour). The virtual whistle board sign 336 corresponds to the physical whistle board sign 236 (FIG. 2A) and includes an indicia 337 (in this example, the letter “W”) communicating the message of the virtual whistle board sign 336.

As shown, the relative distances between the plurality of virtual speed limit signs 334 a-334 b, the indicia 310 representative of the railroad vehicle, the plurality of virtual milepost signs 332 a-332 e, and the virtual whistle board sign 336 along the railroad track indicia 320 correspond to the relative physical locations of the railroad vehicle 100, the physical speed limit signs 234 a-234 b, the physical milepost signs 232 a-232 e, and the physical whistle board sign 236 (FIG. 2A) along the railroad track 200.

In some implementations, the electronic display device 18 also displays one or more substantially real-time distances 340 a-340 c between the current location of the railroad vehicle 100 and the location associated with one or more of the plurality of virtual railroad signs 330. In other words, the substantially real-time distance is a distance between the location actual railroad vehicle 100 and the location along the railroad track 200 associated with the plurality of virtual railroad sign 330, as if the virtual railroad sign were actually placed along the railroad track 200. As shown, the first virtual speed limit sign 334 a includes a substantially real-time distance 340 a between the current location 300 of the railroad vehicle and the associated location of the first virtual speed limit sign 334 a. In this example, the substantially real-time distance 340 a between the current location 300 of the railroad vehicle and the first virtual speed limit sign 334 a is 0.1 miles. The virtual whistle board sign 336 includes a substantially real-time distance 340 b between the current location 300 of the railroad vehicle and the virtual whistle board sign 336 which, in this example, is 0.6 miles. Similarly, the second virtual speed limit sign 334 b includes a substantially real-time distance 340 c between the current location 300 of the railroad vehicle and the second virtual speed limit sign 334 b which, in this example, is 3.1 miles. While not shown, it is contemplated that in some implementations the plurality of virtual milepost signs 332 a-332 e can also include a substantially real-time distance from the current location 300 of the railroad vehicle. As shown, each of the substantially real-time distances 340 a-340 c is positioned within the generally square boundary of the respective one of the plurality virtual railroad signs 330.

When operating the railroad vehicle 100 and viewing the plurality of railroad signs 230 (FIG. 2A), an operator can only estimate how far away the railroad vehicle 100 is from the railroad sign. If the physical railroad sign is a speed limit sign that calls for a reduction in speed, and if the engineer misjudges how far away the sign is (or does not see it), this may cause the PTC system 114 (FIG. 1) to activate and/or require the engineer to rapidly decelerate using the brakes. Advantageously, by displaying a substantially real-time distance between one or more of the plurality of virtual railroad signs 330, an engineer operating the railroad vehicle 100 can more precisely determine when to take any action (e.g., accelerate, decelerate, etc.) that is required by the associated message of the virtual railroad sign.

In some implementations, the electronic display device 18 can also display a current speed of the railroad vehicle 100. The current speed of the railroad vehicle 100 can be an actual, measured speed of the railroad vehicle 100 (e.g., measured using the optical encoder described herein), an expected speed of the railroad vehicle 100 (e.g., based on the speed limit), or a combination of both. In such implementations, the processor 12 of the system 10 can be used to determine an amount of time (e.g., seconds, minutes, etc.) until the railroad vehicle 100 reaches a location associated with one or more of the plurality of virtual railroad signs 330. As one example, based on the current location of the railroad vehicle 100, the current speed of the railroad vehicle 100, and the location associated with the second virtual speed limit sign 334 b, the display device 18 can display an amount of time until the railroad vehicle 100 reaches the second virtual speed limit sign 334 b. For example, if the railroad vehicle 100 is traveling at 60 miles per hour, the amount of time from current location 300 to the second virtual speed limit sign 334 b is about 18.5 seconds. In such implementations, the amount of time can be displayed in addition to the substantially real-time distance described herein, and can be displayed within the boundary of the respective one of the plurality of virtual railroad signs 330. Advantageously, displaying an amount of time provides an engineer operating the railroad vehicle 100 further information to aid in operating the railroad vehicle 100 safely and efficiently (e.g., reducing fuel consumption, allowing more gradual breaking or acceleration, etc.)

As described above, in some implementations, the railroad vehicle 100 includes the camera 112, which is configured to generate image data reproducible as one or more images of the railroad track 200 and its surroundings. These images from the camera 112 can be displayed on the electronic display device 18. The plurality of virtual railroad signs 330 can then be overlaid on these images from the camera 112 to create an augmented reality display. In such implementations, the plurality of virtual railroad signs 330 are overlaid on the images from the camera 112 such that they generally correspond to where the physical railroad sign 230 would be located.

Referring to FIG. 2B, the railroad vehicle 100 is shown at a second, subsequent position (relative to FIG. 2A) as the railroad vehicle 100 has moved along the railroad track 200 in the direction of arrow A. More specifically, after moving in the direction of arrow A for some time, the railroad vehicle 100 has passed the first physical milepost sign 232 a and the first physical speed limit sign 234 a.

Referring now to FIG. 3B, the indicia 310 representative of the railroad vehicle 100 (FIGS. 1 and 2A), the indicia 320 representative of a segment of the railroad track 200 (FIG. 2B), and the plurality of virtual railroad signs 330 corresponding to the plurality of physical railroad signs 232 (FIG. 2B) are displayed on the electronic display device 18 (FIG. 1) when the railroad vehicle 100 is at a second, subsequent location (relative to the location shown in FIG. 2A). In this example, the plurality of virtual railroad signs 330 displayed for the second, subsequent location of the railroad vehicle (FIG. 2B) is the same as the plurality of virtual railroad signs 330 displayed for the first location of the railroad vehicle 100 (FIG. 2A).

As shown by a comparison of FIGS. 3A and 3B, the relative positions of the displayed plurality of virtual railroad signs 330 and the indicia 310 representative of the railroad vehicle have been updated to correspond to the relative distances between each of the plurality of physical railroad signs 230 and the location of the railroad vehicle 100 at the second, sequent location (FIG. 2B). Further, the displayed current location 300 of the railroad vehicle 100 is updated to reflect the second, subsequent location of the railroad vehicle 100 (the railroad vehicle is now located a mile 1.4, having traveled 0.5 from the first location (FIG. 2A) to the second, subsequent position (FIG. 2B)). Moreover, the substantially real-time distance 340 a (FIG. 2A) between the first virtual speed limit sign 334 a and the current location 300 of the railroad vehicle 100 is removed as the railroad vehicle 100 has already passed the location associated with the first virtual speed limit sign 334 a.

While the plurality of physical railroad signs 230 (FIGS. 2A and 2B) and the plurality of virtual railroad signs 330 (FIGS. 3A and 3B) have been shown and described herein as including a plurality of milepost signs, a plurality of speed limit signs, and a whistle board sign, other types and combination of railroads are contemplated such as, for example, a chain-marker, a curve sign, a tunnel sign, a road crossing sign, a rail crossing sign, a bridge sign, an overhead bridge sign, a railroad sign, or any combination thereof. Further, while the displayed indicium of the plurality of virtual railroad signs 330 are shown and described herein as either a number or a letter, other types of indicium are possible, such as, for example, a word, a symbol, a color, an image, or the like, or any combination thereof. For example, instead of being a number, the displayed indicia 335 a of the first virtual speed limit sign 334 a can be a color (e.g., green), communicating to the engineer of the railroad vehicle 100 that the speed limit is the maximum allowed speed for the railroad.

In some implementations, the system 10 can also be used to automatically display a plurality of virtual railroad signs on the electronic display device 18. In such implementations, the memory device 14 stores therein a database that is similar to the database 16 that stores a plurality of virtual railroad signs, where each of the virtual railroad signs is associated with a location along the railroad track and a substantially real-time signal. Examples of substantially real-time signals include, for example, a clear signal (indicating that the railroad vehicle 100 can proceed), an approach-limited signal (indicating that the railroad vehicle 100 can proceed at a limited speed but to be prepared to change speeds), an approach-medium signal (indicating that the railroad vehicle 100 can proceed at a medium speed but to be prepared to change speeds), a diverging-clear signal (indicating that the railroad vehicle 100 can proceed through a diverging route), an approach signal (indicating that the railroad vehicle 100 should proceed but prepare to stop at the next signal), a diverging-approach signal (indicating that the railroad vehicle 100 should proceed through a diverging route and approach the next signal prepared to stop), a restricting signal (indicating that the railroad vehicle 100 should proceed at a restricted speed), a stop and proceed signal (indicating that the railroad vehicle 100 should stop and then proceed), a stop signal (indicating that the railroad vehicle 100 should stop), or any combination thereof. These virtual railroad signals can be automatically selected from the database stored in the memory 14 and displayed on the electronic display device 18 using the methods described herein. For example, in one implementations, the memory device 14 receives, via the communication module 20, updated information from a remote device such that each of the virtual signals stored in the database includes a substantially-real time signal.

Referring to FIG. 4, a method 400 for automatically displaying one or more virtual railroad signs and/or for operating a railroad vehicle without reference to physical signs placed along the railroad track is shown. The method 400 can be implemented using the system 10 (FIG. 1) described herein.

Step 401 of the method 400 includes determining a current location of the railroad vehicle 100 along the railroad track 200 (FIGS. 2A and 2B). As described herein, the current location of the railroad vehicle 100 can be determined using the GPS module 22, the location sensor(s) 24, or a combination thereof.

Step 402 of the method 400 includes automatically selecting a plurality of virtual railroad signs (e.g., the plurality of virtual railroad signs 330 shown in FIGS. 3A and 3B) from the virtual sign database 16 of the memory device 14 (FIG. 1). As described herein, the virtual railroad sign database 16 stores virtual railroad signs (e.g., 100 virtual signs, 100,000 virtual signs, 500,000 virtual signs, etc.), where each of the virtual railroad signs stored therein is associated with a location along the railroad track 200 (e.g., GPS coordinates) and a message (e.g., a speed limit, milepost, etc.) Automatically selecting the plurality of virtual railroad signs is based on the determined current location of the railroad vehicle 100. More specifically, one or more virtual railroad signs with associated locations that are within a predetermined distance from the determined current location of the railroad vehicle 100 are selected from the virtual sign database 16. The predetermined distance is a length of the railroad track 200 in front of the railroad vehicle 100 in the direction of travel (arrow A). The predetermined distance can be, for example, between about 0.1 miles and about 100 miles, between about 0.25 miles and about 50 miles, between about 0.5 miles and about 10 miles, between about 1 mile and about 10 miles, between about 3 miles and about 6 miles, about 5 miles, etc. In some implementations, the predetermined distance can be adjusted as desired by an engineer operating the railroad vehicle 100 (e.g., through an input interface of the electronic display device 18 of the system 10) such that electronic display device 18 displays more or less virtual railroad signs, in greater or less detail.

Step 403 of the method 400 includes displaying an indicia representative of at least a portion of the railroad vehicle 100 on the electronic display device 18. In the example shown in FIGS. 3A and 3B, the indicia 300 representative of the railroad vehicle 100 is an image or depiction of a railroad locomotive, although other types of indicia are possible. For example, the displayed indicia representative of the railroad vehicle 100 can be shape (e.g., a rectangle), a partial image or depiction of the railroad vehicle 100 (e.g., half of the locomotive), or a full or partial image or depiction of an entire rain (e.g., the locomotive and one or more railcars). Step 403 can also including displaying the determined current location of the railroad vehicle 100 (step 401) on the electronic display device 18 (e.g., as shown in FIGS. 3A and 3B).

As described herein, in some implementations, at least some of the components of the system 10 can be decoupled from a railroad vehicle (e.g., the electronic display device 18). As one example, the electronic display device 18 and other components of the system 10 can be integrated in a mobile device (e.g., smartphone, computer tablet, laptop, etc.) that is carried by a railroad maintenance worker traveling (e.g., walking) along the railroad track 200. In such implementations, rather than displaying an indicia representative of at least a portion of the railroad vehicle 100, step 403 can include displaying an indicia representative of the maintenance worker (e.g., a shape, a symbol, an icon, an image or depiction of the worker, etc.)

Step 404 of the method 400 includes displaying an indicia representative of a portion (e.g., segment) of the railroad track 200 (FIGS. 2A and 2B) on the electronic display device 18. As described above, the railroad track 200 includes a substantially linear (e.g., straight) portion 210 and a substantially non-linear (e.g., curved) section 220. As shown in FIGS. 3A and 3B, the indicia 320 representative of the railroad track 220 is linear (e.g., a generally straight line). Further, in some implementations, the portion of the railroad track 220 has a length that is equal to the predetermined distance described above in step 402 for selecting the plurality of virtual railroad signs from the database 16.

Step 405 of the method 400 includes displaying the selected plurality of virtual railroad signs (step 402) on the electronic display device 18. More specifically, step 405 includes displaying an indicia representative of the associated message of the selected virtual railroad signs as shown in, for example, FIGS. 3A and 3B.

Step 406 of the method 400 includes displaying a substantially real-time distance between the determined current location of the railroad vehicle 100 (step 401) and the associated locations of the selected virtual railroad signs. For example, as shown in FIGS. 3A and 3B, a substantially real-time distance 340 a for the first virtual speed limit sign 334 a, a substantially real-time distance 340 b for the virtual whistle board sign 336, and a substantially real-time distance 340 c for the second virtual speed limit sign 334 b are displayed on the electronic display device 18. While the substantially real-time distances are shown in the lower right-hand corner of the virtual railroad signs, more generally, the substantially real-time distances 340 a-340 c can be displayed anywhere on the electronic display device 18.

Upon completion of step 406, steps 401-406 can be repeated one or more times such that the various images displayed on the electronic display device 18 are continuously updated as the railroad vehicle 100 moves along the railroad track 200. For example, as the railroad vehicle 100 continues to move along the railroad track 200 in the direction of arrow A (FIGS. 2A and 2B), the current location 300 (FIGS. 3A and 3B), the positions of the displayed plurality of virtual railroad signs 330 relative to the indicia 310 representative of the railroad vehicle 100 is updated, and the substantially real-time distances 340 a-340 c are continuously updated. In the examples shown in FIGS. 3A and 3B, the plurality of virtual railroad signs 330 move towards the indicia 310 representative of the railroad vehicle 100 as the railroad vehicle 100 continues moves in the direction of arrow A (FIGS. 2A and 2B). Thus, all of the various indicia are displayed on the displayed device 18 in substantially real-time (e.g., with only a very small latency on the order of milliseconds, for example).

It should be understood that when step 402 is carried out a second time to selected a second plurality of virtual railroad signs, the second plurality of virtual railroad signs can be the same as, or different than, the selected plurality of railroad signs the first time step 402 is performed. As shown by a comparison of FIGS. 3A and 3B, the same virtual railroad signs 330 are displayed when the railroad vehicle 100 is at the first location and when the railroad vehicle 100 is at the second, subsequent location. However, it should be understood that as the railroad vehicle 100 continues to move in the direction of arrow A, a different plurality of virtual railroad signs will be automatically selected from the database 16 when step 402 is repeated.

To create the database 16 of virtual railroad signs stored in the memory device 14, the locations of physical railroad signs must be determined and input into the database 16. As described herein, the current location of the railroad vehicle 100 along the railroad track 200 is expressed in reference to mileposts along the railroad track 200 (e.g., the railroad vehicle is currently located at mile 1.4). While the locations of the physical railroad signs can be determined in terms of GPS coordinates, these GPS coordinates must then correspond to a distance along the railroad track (e.g., mile 1.0 of the railroad track). In one example, a geographic information system (“GIS”) mapping methodology may be used to generate the database 16.

FIG. 5 illustrates a two-dimensional map 500 of a railroad including a plurality of railroad tracks. As shown, a two-dimensional first railroad track 510 includes a plurality of substantially linear (e.g., straight) sections 512 and a plurality substantially non-linear (e.g., curved) sections 514. FIG. 6 illustrates a linearized (one-dimensional) map 600 of the railroad shown in FIG. 5, including a linearized (one-dimensional) version 610 of the first railroad track 510. As shown in FIG. 5, a plurality of physical railroad signs 530 are positioned along the two-dimensional railroad track 510. Among others, there are two methods for mapping the locations of the physical railroad signs 530 to the linearized version 610 of the first railroad track.

The first of such methods includes determining GPS coordinates of the center of the railroad track 510 at predefined intervals (e.g., every foot) and also determining GPS coordinates of the physical railroad signs 530. Based on this information, the railroad track 510 and the plurality of physical railroad signs 530 can be mapped as the linearized version 610 shown in FIG. 6. The second of such methods includes determining GPS coordinates of the physical railroad signs 530 along the two-dimensional railroad track 510 (FIG. 5) and determining a distance between the GPS coordinates of the physical railroad signs and railroad mileposts to place them along the linearized version 610 of the first railroad track shown in FIG. 6. Of these two methods, the first method is preferred because the second method relies on the assumption that the mileposts are positioned correctly.

In accordance with the aspects described herein, in some implementations, some or all of the physical railroad signs 232 (FIGS. 2A and 2B) can be removed from the railroad track 200 because the engineer can operate the railroad vehicle 100 using the virtual railroad signs 330 displayed on the electronic display device 18 (FIGS. 3A and 3B). There are several advantages to removing the physical railroad signs 230. First, the railroad no longer needs to resurvey the GPS coordinates of physical railroad signs to ensure that the PTC system database is compliance with government regulations. Second, by transmitting an update to the database 16 stored in the memory device 14, a railroad can quickly update one or more signs (e.g., a speed limit) without having to send workers to replace physical signs. Third, the railroad engineer's ability to receive messages from railroad signs is not limited by the extent of the engineer's visual line-of-sight, which can be limited by various factors (e.g., inclement weather, a curve, the terrain, etc.) Rather, the predetermined distance can be adjusted so that the engineer can receive messages from railroad signs that are farther ahead of the railroad vehicle than the engineer would be able to see. Fourth, by displaying the linearized indicia 320 of the railroad track 200 and/or displaying substantially real-time distances between the virtual signs 330 and the current location of the railroad vehicle, engineers can better anticipate what actions need to be taken to comply with the message of the railroad signs (e.g., speed up, slow down, stop, etc.) The systems and methods described herein can also be used to facilitate the operation of autonomous railroad vehicles

While the various distances described herein are expressed in terms of miles, more generally, any unit of distance (e.g., feet, meters, kilometers, etc.) or any combination of units of distance can be used in accordance with the systems and methods described herein.

While the present disclosure has been described with reference to one or more particular embodiments or implementations, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present disclosure. Each of these embodiments or implementations and obvious variations thereof is contemplated as falling within the spirit and scope of the present disclosure. It is also contemplated that additional embodiments implementations according to aspects of the present disclosure may combine any number of features from any of the embodiments described herein. 

What is claimed is:
 1. A method for operating a railroad vehicle on a railroad track without reference to physical railroad signs located generally along the railroad track, the method comprising: determining a current location of the railroad vehicle along the railroad track; based on the determined current location of the railroad vehicle, automatically selecting a virtual railroad sign from one or more databases containing a plurality of virtual railroad signs, each of the plurality of virtual railroad signs stored in the one or more databases being associated with (i) a respective location along the railroad track and (ii) a respective message; and displaying, on an electronic display device: a railroad track indicia representative of a segment of the railroad track; a railroad vehicle indicia representative of at least a portion of the railroad vehicle; and an indicia representative of the associated message of the selected virtual railroad sign.
 2. The method of claim 1, further comprising: determining a substantially real-time distance between the current location of the railroad vehicle and the associated location of the selected virtual railroad sign; and displaying, on the electronic display device, the substantially real-time distance between the current location of the railroad vehicle and the selected virtual railroad sign.
 3. (canceled)
 4. The method of claim 1, wherein the segment of the railroad track includes non-linear portions and the displayed railroad track indicia representative of the segment of the railroad track is linear.
 5. (canceled)
 6. The method of claim 1, wherein the associated message of the selected virtual railroad sign includes a milepost number, a speed limit, a limit, a whistle board, an indication of a railroad track curve, an indication of a railroad track tunnel, an indication of a road crossing, an indication of a rail crossing, an indication of a bridge, an indication of an overhead bridge, a railroad grade, or any combination thereof.
 7. The method of claim 1, wherein the selected virtual railroad sign is within a predetermined distance from the determined current location of the railroad vehicle, wherein the predetermined distance is between about 1 mile and about 10 miles. 8-10. (canceled)
 11. The method of claim 1, further comprising, based on the displayed indicia representative of the associated message of the selected virtual railroad sign, automatically adjusting a speed of the railroad vehicle.
 12. (canceled)
 13. The method of claim 1, further comprising, based on the determined current location of the railroad vehicle, automatically selecting a virtual railroad signal from a plurality of virtual railroad signs stored in the one or more databases, each of the plurality of virtual railroad signals being associated with (i) a location along the railroad track and (ii) a substantially real-time signal; and displaying, on the electronic display device, an indicia representative of the real-time signal associated with the selected virtual railroad signal.
 14. The method of claim 13, wherein the associated substantially real-time signal of the selected virtual railroad signal is a clear signal, an approach-limited signal, an approach-medium signal, a diverging-clear signal, an approach signal, a diverging-approach signal, a restricting signal, a stop and proceed signal, or a stop signal.
 15. The method of claim 1, wherein the electronic display device is positioned with and coupled to the railroad vehicle.
 16. The method of claim 1, wherein physical signs corresponding to the plurality of virtual railroad signs stored in the one or more databases are not located along the railroad track.
 17. A method for operating a railroad vehicle on a railroad track without reference to physical railroad signs located along the railroad track, the method comprising: determining a current location of the railroad vehicle along the railroad track; based on the determined current location of the railroad vehicle, automatically selecting a plurality of virtual railroad signs from one or more databases, each of the plurality of virtual railroad signs being associated with (i) a respective location along the railroad track and (ii) a respective message; and displaying, on an electronic display device: a railroad track indicia representative of a segment of the railroad track, a railroad vehicle indicia representative of at least a portion of the railroad vehicle, and for each of the selected plurality of virtual railroad signs, an indicia representative of the associated message.
 18. The method of claim 17, further comprising: determining a substantially real-time distance between the current location of the railroad vehicle and each of the associated locations of the selected plurality of virtual railroad signs; and displaying, on the electronic display device, the substantially real-time distance between the current location of the railroad vehicle and each of the selected plurality of virtual railroad signs.
 19. (canceled)
 20. The method of claim 17, wherein the segment of the railroad track includes substantially non-linear portions and the displayed indicia representative of the segment of the railroad track is linear.
 21. The method of claim 17, wherein the associated messages of the selected plurality of virtual railroad signs include a milepost number, a speed limit, a limit, a whistle board, or any combination thereof. 22-25. (canceled)
 26. The method of claim 17, wherein the selected plurality of virtual railroad signs includes a first virtual sign, a second virtual sign, and a third virtual sign, wherein the associated message of the first virtual sign is a first speed limit, the associated message of the second virtual is a whistle board, and the associated message of the third virtual sign is a second speed limit that is different than the first speed limit.
 27. The method of claim 26, further comprising, determining a substantially real-time distance between the current location of the railroad vehicle and the associated location of the first virtual sign, the second virtual sign, and the third virtual sign; and displaying, on the electronic display device, the substantially real-time distance between the current location of the railroad vehicle and the first virtual sign, the second virtual sign, and the third virtual sign.
 28. The method of claim 17, further comprising, based on the determined current location of the railroad vehicle, automatically selecting a virtual railroad signal from a plurality of virtual railroad signs stored in the one or more databases, each of the plurality of virtual railroad signals being associated with (i) a location along the railroad track and (ii) a substantially real-time signal; and displaying, on the electronic display device, an indicia representative of the real-time signal associated with the selected virtual railroad signal.
 29. The method of claim 17, wherein the associated substantially real-time signal of the selected virtual railroad signal is a clear signal, an approach-limited signal, an approach-medium signal, a diverging-clear signal, an approach signal, a diverging-approach signal, a restricting signal, a stop and proceed signal, a stop signal, or any combination thereof. 30-31. (canceled)
 32. A method for automatically displaying one or more virtual railroad signs, the method comprising: determining a location of a railroad vehicle along a railroad track at a first time; based on the determined location of the railroad vehicle at the first time, automatically selecting a first plurality of virtual railroad signs stored in one or more databases, each of the virtual railroad signs stored in the one or more databases being associated with (i) a respective location along the railroad track and (ii) a respective message; displaying, on an electronic display device: a railroad track indicia representative of a first segment of the railroad track, a railroad vehicle indicia representative of at least a portion of the railroad vehicle, and for each of the selected first plurality of virtual railroad signs, an indicia representative of the associated message; determining a location of the railroad vehicle along the railroad track at a second time; based on the determined location of the railroad vehicle at the second time, automatically selecting a second plurality of virtual railroad signs from the one or more databases, each of the plurality of virtual railroad signs being associated with (i) a respective location along the railroad track and (ii) a respective message; and displaying, on the electronic display device: a railroad track indicia representative of a second segment of the railroad track, the railroad vehicle indicia representative of at least a portion of the railroad vehicle, and for each of the selected second plurality of virtual railroad signs, an indicia representative of the associated message.
 33. The method of claim 32, wherein the selected first plurality of virtual railroad signs is different than the selected second plurality of virtual railroad signs. 34-54. (canceled) 